WO1991016745A1

WO1991016745A1 - Laser device

Info

Publication number: WO1991016745A1
Application number: PCT/JP1991/000495
Authority: WO
Inventors: Hideaki Shibata; Ken Ohmata; Mitchito Uehara; Mitsugu Terada; Yasuo Oeda; Yuichiro Terashi
Original assignee: Mitsui Petrochemical Industries, Ltd.
Priority date: 1990-04-16
Filing date: 1991-04-16
Publication date: 1991-10-31
Also published as: CA2059134A1

Abstract

This invention relates to a technique being effective in applying it to the control of the oscillation wavelength and output of a laser device. The object thereof is that the inclination of a wavelength selecting element such as an etalon is adjusted with high accuracy and the wavelength of the laser output of a laser resonator is made always stable. A laser device having at least first and second wavelength selecting elements which are aligned on an optical path and make the bandwidth of the laser beam narrow by adjusting the inclination of at least one of the elements, is provided with an automatic micrometer head for the fine adjustment of the inclination. By using the automatic micrometer capable of controlling finely the quantity of movment, the inclination to the optical path of the wavelength selecting elements can be adjusted finely. Thereby, the wave length of the laser beam can be always stabilized. Therefore, the laser device can be utilized effectively, for example, for the light source of the lithography process of semiconductor manufacturing.

Description

---Specifi cations Laser equipment technology

The present invention relates to a method of controlling an oscillation wavelength and an oscillation output in a laser device. Background technology

Laser light itself has high wavelength purity, high output, etc., which are coherent, and is regarded as a promising light source capable of intense light. Under these circumstances, a narrow band excimer laser is being considered for use as a light source in the lithographic process in semiconductor manufacturing.

In order to obtain ^^-band laser light, it is known that a laser resonator is composed of a wavelength selecting element such as a grating, a prism, a birefringent filter, and an aperture. Furthermore, in Roar one laser medium by having a laser gain a wide band as an excimer laser or a dye laser, one or a plurality of etalons known force ^s' to be inserted into the laser ^ in the converter to the narrowing I have.

Here, the etalon will be described briefly. The etalon applies the multi-S dimension of light generated between two highly-flat H-layers, which are plated at a predetermined interval, and the phenomenon of interference. This is a wavelength selection element.

FIG. 6 shows a laser device using such an etalon. Here, a first and a second pair of etalons 25a and 25b are used to achieve a multi-region. That is, the first etalon 25a functions as a coarse adjustment for narrowing the band, and the second etalon 25b functions as a fine adjustment. That is, the laser light emitted from the laser medium 26 is irradiated by the rear illuminator 27, and then the first etalon 25a coarsens the original laser oscillation wavelength range. This is further narrowed down to the desired bandwidth by 5b and the output is output ft, and is illuminated from the laser unit 29 via the front mirror 28. Here, in order to stabilize the wavelength of the laser light emitted from the laser device 29, the following method was used.

That is, the laser beam emitted from the laser device 29 is split by the beam splitter 30, and the split laser beam enters the wavelength measuring unit 33 via the optical fiber cable 32. The wavelength measuring section 33 measures the center wavelength, and outputs the insulted measurement signal to the main control section 34. The main control unit 34 executes a predetermined calculation process based on the measurement signal, and the pneumatic or hydraulic actuators 36 a and 36 b for changing the pneumatic or hydraulic pressure through the J interface 35. The etalons 25a and 25b were adjusted to optimal positions by drawing only 4 points.

Therefore, among the laser beams illuminated by the laser 9, [: In order to stabilize the length, there is a method for surely performing fine adjustment of the above-mentioned ETA ports 25 a and 25 b. .

By the way, in the case of transversal processing such as semiconductor manufacturing, it is necessary to obtain a high degree of wavelength stability in long fiber-like irradiation. It has to be suppressed.

However, the actuators 36a, 36b due to the pneumatic, hydraulic, or spring pressure changes have a minimum zenji position, that is, it is difficult to finely adjust the tilt angle of the etalons 25a, 25b. 7 o to obtain a high level of laser wavelength

The present invention has been made in view of the above point, and an object of the present invention is to adjust a tilt angle of a wavelength selection element such as an etalon with high accuracy and always stabilize a laser output wavelength from a laser device.

In laser equipment, laser output power is high, but as a premise of feedback control to stabilize laser output, laser output must be measured reliably. .

In addition, it is necessary to cut off noise from the power supply unit in order to stabilize the laser output, and it is also necessary to be able to appropriately control the entire device. Disclosure of the invention

An object of the present invention is to provide a laser device that can meet a demand such as mi. In order to achieve the above object, the present invention (the first invention) has at least a first arrangement in which laser light from a laser medium is localized by adjusting at least one of the tilt angles arranged in series in a row. In the laser device having the first and second wavelength selection elements, the laser device is provided with an automatic micrometer head for finely adjusting the tilt angle.

According to the above-mentioned means, by using an automatic micrometer head capable of controlling the movement amount very finely, it becomes possible to finely adjust the inclination angle of the wavelength selection element with respect to the angle. As a result, the wavelength of the laser light output from the laser resonator can always be stabilized, and

The automatic micrometer head is, for example, an actuator that has a structure in which an iil: flow motor, a pulse motor, or the like is used, and the rotation of such a motor is converted into movement in a window direction to move the head. It is.

As the wavelength selection element to be shelf in the present invention, an etalon's general diffraction ^ ", 麵 -fold filter or the like can be used. A combination with etalon may be used.

Examples of lasers suitable for controlling the laser oscillation output and wavelength according to the present invention include excimer lasers such as KrF and ArF, such as carbon dioxide gas laser, copper vapor laser, alexandrite laser, and Ti —Sapphire lasers, dye lasers, etc. Next, a description will be given of a second invention for improving the measurement reliability of laser oscillation output detection. An object of the present invention is to realize a laser device capable of accurately measuring a laser oscillation output without being influenced by electromagnetic noise from a laser medium or the like, and capable of performing a stable laser oscillation at a high level. is there.

The second light source includes a light receiving unit disposed in the vicinity of the laser medium, an optical fiber having one end connected to the light receiving unit for transmitting detection light from the laser medium, and a light emitting unit connected to the other end of the optical fiber. A light section, a photoelectric conversion element disposed opposite to the light emitting section, and a photoelectric conversion element. The gist of the present invention is a laser oscillation output detection device including a main control unit that calculates an oscillation output of the laser light based on a detection signal from a switching element and generates a control signal to the laser medium.

Here, lasers include excimer lasers such as KrF and ArF, carbon dioxide lasers, copper vapor lasers, dye lasers, YAG lasers, and alexandrite lasers. A laser that oscillates, such as a helium-neon laser or an argon laser, may be used as well as a laser device that oscillates.

Also, the receiving and emitting lights connected to the 两 end of the optical fiber may be provided with a bright lens to increase the light input efficiency or the light output efficiency.

The photoelectric conversion element is, for example, an element such as a photodiode, and may be any element having a photoelectric effect of generating an electric signal corresponding to reception.

According to the above-described means, the detection light received by the receiver disposed near the laser medium is guided by the optical fiber in an optical state. Then, the light is emitted from a light emitting unit provided at a ray position which is not affected by the electromagnetic noise of the laser medium, and this light is received by a photoelectric conversion element.

As described above, in the present invention, by using the optical fiber, the distance between the laser medium and the photoelectric conversion element is increased, and the photodiode is arranged in close proximity to the detecting unit, thereby making it possible to obtain the electromagnetic wave from the laser medium. The effect of dynamic noise can be suppressed. In addition, the time from the photoelectric conversion element to the drive / detection unit can be significantly reduced.

As a result, the level of the noise signal as the output signal of the photoelectric conversion element is reduced, and signal detection that is not hindered by noise becomes possible. Thus, the laser device can be reliably controlled based on such a detection result. The third invention aims to measure the laser emission 5 ^ with high reliability, and converts a detection signal, which is received by the laser beam receiving element and a photodetector, into a digital signal. It employs an A / D conversion unit and arithmetic means for analyzing a signal from the A / D conversion unit to calculate a laser oscillation output, and at least between the receiver and the A / D conversion unit. That an integration circuit with multi-stage integrators is interposed The gist of the present invention is a laser oscillation output detection device which is defined as-.

Here, the laser is a pulsed laser such as an excimer laser, a carbon dioxide laser, a copper vapor laser, a color laser, a YAGG laser, an alexandrite laser, a helium-neon laser, an argon ion laser, or the like. The vibration laser may be used.

Further, the light receiving element may be a photoelectric element such as a photodiode, for example, as long as it generates an electric signal corresponding to the light receiving fi.

The preceding circuit can be realized by a circuit configuration in which, for example, integrators are connected in multiple stages as an integrator. Power that can be extended to ^ $ favorable o

According to the above-described means, the light intensity as a light amount is detected by integrating this value with respect to time by focusing on the fact that the output of the light receiving element represents the time distribution of the light intensity, so that more accurate Light can be detected. The fourth invention is a laser that does not diffuse noise to the outside of the housing or to the power supply side, and in particular, greatly improves isolation between a computer and a high-voltage system, thereby preventing abnormal operation of the computer. The purpose is to make the equipment Hi.

A fourth invention has the following configuration in a laser device having a high-voltage generation device for supplying a high voltage to a discharge electrode in a gas laser chamber, and a computer for controlling the high-generation device.

That is, a first shield is provided on a first power supply line connecting the high voltage generator and a power supply.

Insert a noise filter in the middle of the first power source.

Then, provide a second shield on the second power line connecting the power supply 3 and the computer.o

A third shield is provided on the high voltage cord between the high voltage generator and the discharge electrode. Further, a laser device was used as a control cable connecting the high-power generation device and a computer as an optical cable.

Nets and flexible shields with high shielding properties --Pipes are suitable, and it is desirable to ground them.

Further, the noise filter may be an absolute transformer or a single pass filter. Furthermore, it is better to apply shielding / filtering to parts where noise is likely to leak.

Medium waves from the high SE generator are forced by the noise filter and do not enter the power supply. Therefore, spurious and pulsating noises do not enter the computer or other circuits via the power supply. Further, the shields prevent noise caused by electromagnetic induction from being applied to the power supply line.

Also, since the computer inputs and outputs data via optical cables, the isolation from noise is ^: and there is no danger. The fifth invention aims to realize a highly reliable gas supply control by preventing the operation of laser gas supply control in the system.

The fifth invention is a laser gas supply device for supplying and exhausting a laser gas into a laser chamber, wherein the laser gas of the gas source connected between a gas source and a laser chamber is introduced into the chamber. To the main piping for controlling the opening and closing of the main piping, which is provided on the piping by the fluid pressure from the t ^ separated position through the control piping, and controls the opening and closing of the main piping. And a pressure detector connected to the end of the branch pipe from the main pipe, and a control connected to the solenoid valve device and the pressure detector by m ^ se ^. A laser that has a sufficient distance between the control pipe and the fl¾ss pipe so that the 配線 ^ wiring is not affected by electromagnetic noise generated in the laser chamber. Gas supply

That is, a valve for controlling the opening and closing of the main pipe is a fluid pressure drive valve, a control pipe for supplying and controlling the driving fluid pressure and an electromagnetic valve device are provided, and a pressure detector is connected to a branch pipe from the main pipe. It has a body especially at the point.

According to the above-mentioned means, the valve for controlling the opening and closing of the main pipe is set to j »: ^ :, which is not affected by electromagnetic noise, by a fluid pressure such as ^ :, and the pressure detector is also divided into n«. Tube bow I. By turning it away from the laser chamber. --Therefore, it is very important to keep all the electric springs in the control system away from the laser chamber.

Therefore, the accuracy of the value detected by the pressure detector is ensured without being affected by the electromagnetic noise generated in the laser chamber. Similarly, malfunction of the valve that opens and closes the main piping is also prevented.

It should be noted that the gas supply / discharge having the above can be used for a gas laser device which is not a sealed type. A sixth object of the present invention is to provide a gas laser control device having a plurality of control items having different processes, in which a single control device can execute a plurality of control items in parallel. is there.

According to a sixth aspect of the present invention, there is provided a high-speed timer counter that performs at least a high-level request and a high-level β-clock, and a high-speed timer counter that performs the high-speed β clock. The gist of the present invention is a gas laser control device whose processing timing is determined by a low-speed timer counter that generates a clock for use.

According to the above-mentioned means, a control device is constructed based on a dedicated microprocessor (CPU), and an arbitrary frequency is synthesized from a clock signal. 2: By making full use of a JLh timer counter, high-speed arithmetic processing can be performed. It also supports low-speed arithmetic processing. For example, parallel I / O, digital-to-analog conversion, analog-to-digital conversion I / O, and optical input / output ports are added to this system. In addition, time-sharing is implemented on the software. Incorporating the processing of the marrow control during the processing of the high-speed control enables the parallel processing of multiple control items. As a result, for example, Takashi Osamu can execute another control of the gas or the like without stopping the laser keying.

In the sixth aspect, the control items at the high level are at least output of a discharge start signal, detection of a laser output and output of a stabilization control signal thereof, detection of a laser wavelength and output of a stabilization control signal thereof, The control item in the above g¾kS¾ shall be at least the output of the gas valve opening / closing control signal in gas exchange. --Power is good. ii, the first to sixth inventions can be incorporated in a laser device by selecting and combining 2 J ^ ± each. Brief description of drawings

FIGS. 1 to 5 show difficult examples of the present invention (first invention). FIG. 1 is a block diagram showing the complete arrangement of a laser device, and FIG. Fig. 2 (b) shows the etalon holder for explaining the step of adjusting the brightness, Fig. 2 (b) shows the etalon holder, Fig. 2 (b) shows its side view, and Fig. 3 shows the control for stabilizing the center wavelength. FIG. FIG. 4 is a diagram showing the structure of the automatic micrometer head. FIG. 5 is a block diagram of the main control unit. FIG. 6 is a block diagram showing the entire configuration of the laser device in the ^ technology.

FIG. 7 is an example of the second invention, and is a block diagram showing a configuration of a laser oscillation output detection device.

8 to 10 show an example of the third invention. FIG. 8 is a block diagram showing a configuration of a laser oscillation output detecting device, and FIGS. And FIG. 10 is an explanatory diagram showing outputs and waveforms of the dividing circuit. FIG. 10 is a circuit diagram showing a specific configuration of the integrating circuit.

11 and 12 show ^ in the fourth invention, FIG. 11 is an overall block diagram, and FIG. 12 is a block diagram of a computer part.

FIG. 13 is a block diagram showing an embodiment of the fifth invention, showing a laser gas supply unit.

FIG. 14 shows an embodiment of the sixth invention, and is a block diagram showing a configuration of a gas laser control device.

BEST MODE FOR CARRYING OUT THE INVENTION: II

Hereinafter, the present invention will be described with reference to the drawings.

In the present invention (the first invention), as shown in FIG. On the sides W 1 to W 1, an etalon 3 for fine tuning and an etalon 4 for fine tuning are arranged as wavelength selecting elements. A rear mirror 15 is disposed at the outermost position. After the laser beam generated by the laser medium 2 is K-sized by the rear mirror 5, it is narrowed to a wavelength band of about 1/10 by the coarse adjustment etalon 3. Bandwidth is finely adjusted by the etalon 4 for fine adjustment to about 1/10 of it.

The laser beam sized in this way is branched by the beam splitter 6 disposed on;) ^, and enters the wavelength measuring unit 8 from the optical fiber cable 7 to detect its oscillation wavelength. Is done. Then, the main control unit 10 receiving the detection signal performs a predetermined arithmetic process, and outputs a control signal to the DC motor driver 11. The DC motor drino 11 finely adjusts the coarse adjustment etalon 3 and the fine adjustment etalon 4 based on this control signal. Such fine adjustment is performed by performing IHSJ on the automatic micrometer heads 14a to 14d.

Here, the fine adjustment technique will be described with reference to FIG.

That is, a pair of the automatic micrometer heads 14a to 14d are arranged on one diagonal line on the plane of the rectangular etalon holders 15 and 16 holding the etalons 3 and 4, respectively. An automatic micrometer head 14a, 14d for fine adjustment of the left and right displacement of the etalons 3 and 4, and an automatic micrometer head 14b, 14 for fine adjustment of the tilt angle of the etalon with respect to ^ B & c. Each of the automatic micrometer heads 14a to 14d is controlled by a DC motor driver 11 in response to a control signal from the main control unit 10.

Here, the automatic micrometer heads 14a to 14d will be briefly described. There are a micro DC motor as a direct means inside and a high-performance gear head inside. In addition, the gearhead has a structure in which the lead screw is rotated by a motor, and the rotation of the motor is converted into a moving amount of the lead screw in a linear direction.

For example, as shown in FIG. 4, the automatic micrometer head includes a linear slide head 20b, a lead screw 20c, a Takatoh Noh gear head 20d, and a The miniature DC motor 20 e is provided with a small DC motor 20 e. --The main control unit 10 controls e.

The linear slide head 20 b has a single rod-like portion 20 f, and has a protruding rail til «force ^s cylindrical portion 20 g from the case 20 a. Female screw 20 h is cut. The lead screw 20c is rod-shaped and inserted into the cylindrical portion 20g of the linear slide head 20b. The lead screw 20c is inserted into the female screw 20h on the inner surface of the cylindrical portion 20g. A matching male screw 20 i is cut around.

The high-defect gear head 20d converts the torque of the DC motor 20e using a combination of gears (not shown). Foreword The control unit 10 controls the rotation amount and rotation of the DC motor 20e. More specifically, as shown in FIG. 5, the main control section 10 includes a target ifiia means 21 for setting a target yarn length of a target spectral domain, and a target value setting means 21. »Difference detecting means 22 for detecting the deviation of the measurement center wavelength detected by the wavelength measuring section 8 from the center wavelength, and the automatic micrometer head in a direction for canceling the detection detected by the deviation detecting means 22. And a control means 23 for sending a signal for controlling the rotation amount and the rotation of the DC motor to the motor.

As described above, the automatic micrometer heads 14a, 14d for fine adjustment of the lateral deviation, and the automatic micrometer heads 14b, 14d for fine adjustment of the tilt angle. The fine adjustment of the tilt angle is an important factor for the wavelength stabilization control.By using the automatic micrometer head of the above configuration, the tilt angle adjustment is 0.04 mrad. High-precision fine adjustment of / sec / degree is possible. Next, specific wavelength stabilization control using the present apparatus will be described.

In the wavelength stabilization control of this difficult example, first, the target value setting means 21 determines the target of the broadened spectrum. Then, at the age at which the measured center wavelength detected by the wavelength measuring unit 8 deviates from the above-mentioned fiSi center wavelength, the deviation is detected by the deviation detecting means 22, and the deviation is detected by the control means 23 of the main control unit 10. Control is performed by a control signal (feedback signal) to eliminate the deviation.

That is, as shown in FIG. 3, the desired center wavelength λ ₀ of the laser beam is determined while monitoring the wavelength measuring unit 8, and in this state, the DC motor drinometer 1 is locked and the etalons 3 and 4 are locked. Temporarily fix the position of.

Next, the laser beam radiated from the laser unit 9 is applied to the wavelength measuring unit 8 over time. When the measured center wavelength is shifted by Δs from the center wavelength, the main control unit 10 finely adjusts the position of the etalons 3 and 4 on the optical path with respect to the etalons 3 and 4. Is output to the DC motor driver 11. In other words, here, of the four automatic micrometer heads 14a to l4d, 傾 fine adjustment of the tilt angle mainly for the automatic micrometer head 14d that controls the tilt angle of the etalon 4 Will be.

At this time, the DC motor in the automatic micrometer head 14d is rotated clockwise or counterclockwise depending on whether the muss. Rotate a predetermined amount clockwise. Here, the control parameters in the main control unit 10, such as the rotation direction of the DC motor, the »m Jigfil time, etc., are previously set to a predetermined address in the Iff page area having the main control unit 10 power ^s . And

Using the one-dimensional photodiode array, the center wavelength stabilization ^^ by the above device configuration was operated at 80 Hz for 1 hour to measure the fluctuation state of the measured center wavelength. As a result, a high wavelength was obtained with a center wavelength width of 0.57 pm. It should be noted that an automatic micrometer head having an encoder for detecting the motor rotation fi may be used.> With this encoder, an encoder is provided between the spindle and the gear head. The lost motion (unnecessary movement) and backlash (reverse rotation) of the spindle are not counted. Next, a description will be given of an example of the second invention in which the measurement reliability of the laser vibration output detection is improved.

In FIG. 7, a laser beam 103 emitted from an emission port 102 of a laser device 101 having a laser medium is split by a beam splitter 104 into a light beam. Light is incident on 105. The laser beam 103 is guided to a light emitting unit 107 located at a position 1 through an optical fiber 106 connected to a light receiving unit 105. Here, it is preferable that the first distance 1 be determined according to an output standard or the like for the laser medium 2 itself.

A photodiode as a photoelectric conversion element 110 is placed at a position facing the light emitting unit 107 via an ND filter 108. In the photodiode, — — Light-emitting section The output ¾E changes depending on the light of 107 colors.

The detection unit 111 performs signal processing such as A / D conversion on the input signal from the photodiode and outputs the processed signal to the control unit 112.

The control unit 112 includes a microprocessor, a memory, and the like, performs a predetermined arithmetic process based on the measurement signal from the detection unit 111, and generates a control signal for the laser resonator 101: I do. This control signal is transmitted to the laser device 101 or a laser control mechanism (not shown) through the control line 113 to control the laser beam emitted from the laser device 101.

At this time, the control signal ^; method is to store in the memory the ideal control parameters that are paired with the light daughter obtained by sampling in advance, and the drive signal from the detection unit 111 There is a method of sequentially changing these control parameters in response to the above.

At this time, in the example of 距離, since the distance between the laser resonator 101 and the photoelectric conversion element 10 can be sufficiently secured by the optical fiber 106, the photoelectric conversion element 110 is set to レーザIt can be arranged close to the detection unit 111. For this reason, the influence of the electromagnetic noise generated in the laser difficulty device 101 can be minimized. Moreover, the electricity 114 from the photoelectric conversion element 110 to the detection unit 111 can be greatly reduced.

As a result, the level of the noise signal, which is the output signal of the photoelectric conversion element 110, is reduced, and the signal can be detected without being disturbed by the noise. be able to.

According to the present invention, a stable laser output can be obtained by reliable control of the laser device as a result of signal detection not hindered by noise. An embodiment of the third invention will be described.

As shown in FIG. 8, the laser beam 203 emitted from the emission port 202 of the laser 201 having a laser medium is separated into "" ^ This split light enters the element 205. The pulse detection signal, which was photo-electrically damaged by the light-receiving element 205, is subjected to wavelength adjustment by the integration circuit 206, and then to the A / D converter 7 Is converted into a digital signal and input to the control unit 208. The control unit 208 is configured by, for example, a CPU that includes arithmetic means and registers, and an external storage device such as a memory. After performing predetermined arithmetic processing based on the pulse detection signal, the control unit 208 transmits a control signal to the laser unit 201. Generate This control signal is output to the laser resonator 201 or a laser control mechanism (not shown) through the control line 210 to control the intensity ^{s of the} laser light emitted from the laser 201.

Next, a specific configuration of the integration circuit 206, which is a bell-shaped point of the ^ Sfe example, will be described.

As shown in FIG. 10, the integrator circuit 206 is composed mainly of four-stage OP amplifiers 211a, 211b, 211c, and 211d. The 〇P amplifier 211a functions as an amplification stage, and its gain is made variable by selecting the resistance between the (-) input and ground.

Then, integration of the pulse detection signal is performed by the second to fourth stage OP amplifiers 2 lib, 211 c, and 211 d.

Here, in the same figure, in the 2nd and 3rd stage OP amplifiers 2 lib and 211c, each capacitor of 150 PF is charged to λ¾ voltage and each integration The calculation is performed by giving the initial value to the container.

As the amplifier described above, for example, an amplifier having a hoof width of 8.0 MHz and a slew rate of about 25 V / s can be used. In this way, by configuring the integration circuit 206 using the multi-stage integrator, the rise-decay time of the detection pulse signal of about several tens ns from the light receiving element 205 as shown in FIG. It can be the signal shown in Fig. 9 (b), which extends to 10s. Therefore, a pulse detection signal corresponding to the avoidance of the A / D converter 7 can be obtained, and accurate detection of the light intensity can be performed.

Further, according to this difficult example, since the integrating circuit 206 is configured by using four stages of the OP amplifiers, the characteristic of the integrating circuit 206 is not deteriorated even during long-term use, and the pulse detection signal is not deteriorated. Integration becomes possible.

According to the present invention, the point at which the output waveform of the light receiving element represents the time distribution of light intensity is obtained. In particular, since the light intensity is detected by integrating this value with respect to time, more accurate light detection becomes possible. A fourth embodiment of the invention will be described with reference to FIGS. 11 and 12. FIG.

A discharge 11 is provided in the gas laser chamber 310. Gas control device 3 2 1 connected to gas laser chamber 3 10 via pipe 3 20: ^ Gas control device 3 2 3 connected to gas control device 3 2 1 via pipe 3 2 2 ing. Thus, the gas laser champer 310 is filled with the mixed gas composed of the above-described components. A high E generator 301 is connected to m 311 via a high voltage cord 3 12, and a third shield 3 13 is provided around the high voltage cord 3 12. The height of the high-pressure generator 301 is controlled by a computer 302. The high SEE research device 301 is connected to a power source 303 via a first M304, and the first shield 304 is connected to the first power4. In the middle of the first power supply 304, an insulation transformer as a noise filter 303 is inserted.

Further, the second power supply 7 for connecting the power supply 3 and the computer 302 is provided with a second shield 308.

The control line between the height generator 301 and the computer 302 is an optical cable 9. The interface between the optical cable 309 and the computer 302 is as shown in Fig. 2, and the optical cable 309 is first input to the optical modem 302a and the input / output circuit 302b is connected to it. Connected to the MPU302c via MPU302 ^: ^ ± RAM302d, ROM302e connected. This MPU302c is shielded by itself.

Note that a valve factory (not shown) in the gas control device 321 is also controlled by a computer 302, and the control line 324 is also an optical cable. A shield 326 is also provided on a power supply line 325 connecting the gas control device 321 and the power supply 303.

The gas laser chamber 310, the high-pressure generator 310, the computer 302, the noise filter 303, and the gas control device 321 are housed inside a housing (K). The housing (K) and each shield are grounded GND.

: By configuring as Lh, it is possible to suppress and prevent power line noise and ¾ dimensional noise. That is, the power line noise is discharged. The reflected SE wave generated by the discharge ¾ 3 1 1 enters the power supply 3 0 3 through the guest SE generator 3 0 1, and leaks to each part from here. The reflected component is absorbed by the filter 306 and does not reach the power supply 3. Also ¾! Dimensional noise does not reach the power supply due to each shield.

As with hiE, the stability and certainty of IM can be ensured.

According to the present invention, since a power supply line serving as a noise source is shielded and a noise filter is inserted into the high power supply line, noise leaking to the outside of the housing or to the power supply side can be significantly suppressed.

Furthermore, since the high-frequency generator and the computer that controls the high-frequency generator are connected by an optical cable, the isolation of the user is improved and abnormal operation of the computer can be prevented. An embodiment of the fifth invention will be described.

FIG. 13 is a configuration diagram of a laser gas supply and apparatus according to an embodiment of the present invention. In the figure, a device relating to an excimer laser will be described as an example.

In the figure, a laser chamber 401 is connected to a gas source 402 by a main pipe 403, and a buffer gas, a rare gas, a nitrogen gas and the like are supplied into the laser chamber 401. It is possible. Fluid pressure J | g¾ valves 404 a to 404 c are provided in the middle of the main pipe 403 supplying each gas, so that the mixing ratio of each gas can be adjusted. From the main pipe 403, a pipe 406 connected to a vacuum pump 405 is branched, and in the middle of the pipe 406, a fluid pressure driven valve 4 is provided. 0 4 d The fluid pressure J¾ valves 404 a to 404 d are valves that are opened and closed by the pressure of a fluid such as ^ to control the opening and closing of the main piping 403 and ^: piping 406. , For example, in actuator, etc .: by increasing or decreasing pressure! The structure is such that the movement is converted into the rotation movement of the valve.

Each fluid pressure | g¾ valve 4 0 4 a to 4 0 4d is connected to a control pipe 4 07 a to 4 0 7 d for supplying ^ E, and these control pipes 4 0 7 a ~Four 0 7 d is connected to a solenoid valve unit 8 that controls the supply of ^^ by drawing the distance L.

A branch pipe 410 is provided in the middle of the main pipe 403 extending from the fluid pressure | g¾ valve 404 a to 404 d to the laser chamber 401. The branch pipe 4110 is connected to the pressure detector 411 by being routed at a distance of ¾gg. The pressure detector 411 can detect the state of the pressure in the main pipe 403, that is, in the laser chamber 401.

Foreword The empty pump 405, the solenoid valve unit 408, and the pressure detector 411 are connected to the control unit 412 to control their drooping. The control unit 412 is constituted by, for example, a microprocessor having a memory or the like, and controls the solenoid valve unit 408 based on the detection value of the pressure detector 411 to control the fluid pressure leakage valve. The pressure inside the laser chamber 401 is controlled by adjusting the opening / closing degree of the 404 a to 404 d.

As described above, in this embodiment, the valve mechanism for controlling the opening and closing of the main pipe 403 is driven by fluid pressure, and the pressure detector 411 is branched from the main pipe 403 to a branch pipe 411 which is routed. By connecting, the control system such as the vacuum pump 405, the solenoid valve unit 408, and the pressure detector 411 can be separated from the laser chamber 401, and all the electric wiring can be separated. 0 Can be performed at a position away from 1. Therefore, the gas supply is controlled without being affected by the electromagnetic noise generated in the laser chamber 401! It works.

The length L of the main pipe 406, the control pipe 407a to 407d, and the branch pipe 410 is determined by the vacuum pump 405, the electric unit 408, and the pressure. It is recommended that the detector 411 be set to the minimum distance of the fiber that does not receive the electromagnetic noise of the laser chamber 401. That is, if the RJ distance is too large, the detection accuracy is reduced, and the drive response is reduced.

ADVANTAGE OF THE INVENTION According to this invention, the scene of electromagnetic noise in a gas laser can be reduced and the gas supply operation can be prevented. The invention of the sixth invention »! 1 is a block diagram showing the configuration of the gas laser control device shown in FIG. Description will be made with reference to the drawings.

In the figure, reference numeral 501 denotes a 16-bit or 32-bit system CPU, and according to an instruction from the CPU 501, the height of the output wavelength monitor 509 and the height of the laser ¾1 £ power supply 510, etc., and the gas processing 511, etc. It is configured to be controlled by the force lj.

The output signal from the CPU 501 is output to a high-speed timer counter 502 and a low-speed timer counter 503. These timer counters 502 and 503 each independently count the clock signal CL from the CPU 501 and generate a predetermined high-speed clock signal and low-speed clock signal.

The wavelength monitor control signal and the setting control signal of the output of the high-speed timer counter 502 are converted into digital optical signals via D / A simulators 504 and 505 and photoelectric simulators 507a and 507b, respectively. After being converted into a digital electric signal again through 508a'508b and photoelectric conversion 507a and 507b, the output wavelength monitor device 509 and the high voltage power supply 510 for laser output are controlled. The timing trigger signal control timing which has passed through the high-speed based on a clock signal generator of photoelectric conversion in a parallel TTL output device 506 a 507 c → optical fiber cable ₅ 08 c- photoelectric converter 507 c from the high-speed timer counter 502 at this time Given by

On the other hand, the output from the timer counter 503 is converted to a digital optical signal via the parallel TTL output device 506b and the photoelectric converter 507d.The digital signal is again transmitted via the optical fiber cable 508d and the photoelectric converter 507d. It is converted into an electric signal and sent to the gas processing unit 511 including the laser chamber. In this gas processing 511, a gas exchange operation or the like is executed as a gas valve opening / closing signal or a vacuum pump ON / OFF signal.

As described above, in this example, the high-L glue timer counter 502 generates a time reference for output wavelength monitor control and laser output control for high-speed arithmetic processing, while the low-glue timer counter 503 generates a low-speed glue timer. The time reference for gas exchange control using smoke as arithmetic processing is set to ^; By dividing the time S with a large difference such as JiU by each timer counter and counting to, Without having to stop the control of the other. Further, according to this example, by passing the control signal through the optical fiber cables 508a to 508d, the effect of electromagnetic noise generated from the laser chamber or other drive system can be reduced, but the control system ^ There is also an effect that can prevent the operation. According to the present invention, control based on a plurality of times can be performed by a single control device. Availability of ±± ■

According to the present invention, fine adjustment can be force ^s' performs high-precision result of the wavelength selection element, Le - The ^ ^ can be extremely stable output wavelength in the vessel.

Therefore, it can be used as a shelf for a light source in a lithography process in semi-manufacturing.

Claims

The scope of the claims

(1) A laser device having at least a first and a second wavelength selection element arranged in series on at least one of which adjusts an inclination angle of at least one of the laser light from a laser medium to adjust a tilt angle of the laser light. Laser equipment with automatic micrometer head for fine adjustment of tilt angle go

(2) The laser device according to claim 1, wherein the first wavelength selection element is for coarse adjustment, and the second wavelength selection element is Mffi.

(3) The laser device according to claim 1 or 2, wherein the wavelength selection element is an aperture.

(4) The laser device according to (1), wherein a pair of the automatic micrometer heads are provided on the holder with the wavelength selection element interposed therebetween. So

(5) The laser device according to claim 1, wherein the automatic micrometer head has an encoder for detecting a rotation amount of the motor.

(6) a main control unit for controlling the automatic micrometer head based on the wavelength of the laser light obtained by the wavelength measurement unit, the main control unit having a wavelength measurement unit for the output laser light; Is a target value setting means for setting a reference center wavelength of a target band-narrowing spectrum, and a deviation of a measurement center wavelength detected by the wavelength measurement unit with respect to the center wavelength set by the target setting means. 2. The laser device according to claim 1, further comprising: deviation detecting means for detecting; and control means for transmitting a control signal to the automatic micrometer head in a direction for canceling the deviation detected by the deviation detecting means.

(7) A laser oscillation output detection device for measuring light energy of laser light emitted from a laser device,

A light receiving unit arranged near the laser device;

An optical fiber connected to the other end of the optical fiber optical fiber, which is connected to the light receiving section by one end and transmits detection light from the laser device;

A photoelectric conversion element disposed opposite to the discharge,

A laser oscillation output detection device comprising: a main control unit for calculating an oscillation output of the laser beam based on a detection signal from a photoelectric conversion element and generating a control signal to the laser unit.

(8) A light-receiving element that receives the laser beam, an A / D converter that converts the electrical signal detected by the light-receiving element into a digital signal, and laser oscillation that analyzes the signal from the A / D converter Calculating means for calculating an output, wherein an integrating circuit having at least a multi-stage integrator is interposed between the light receiving element and an A / D converter. Output detector So

(9) In a laser device having a high-frequency generator for supplying a high voltage to a discharge electrode in a gas laser chamber and a computer for controlling the high-ME generator, a first device for connecting a high-SE generator and a power source is provided. A first shield is provided on the power supply line, a noise filter is interposed in the middle of the first power supply, and a second shield is provided on the second power supply connecting the power supply and the computer. A third shield is provided in a high-voltage cord between the high-voltage cord and a control line for connecting the high-frequency generator and a computer to an optical cable.

(10) a laser gas supply for supplying a laser gas into the laser chamber;

Connected between the gas source and the laser chamber: ^ a main pipe for introducing the laser gas of the gas source into the chamber;

Foreword Fluid pressure that is provided on the piping and is controlled by the fluid pressure from the separated position through the control piping to control the opening and closing of the main piping.

An electromagnetic device connected to 制御 5 of the control pipe,

The pressure sensor connected to «5 of the branch pipe from the pipe,

A control unit electrically connected to the electromagnetic device and the pressure detector by an electric wire, and a control unit for electrically controlling these;

By making the piping distance between the control pipe and the branch pipe long enough, the electric rooster does not receive the view of the electromagnetic noise generated by the laser champer.

(11) At least a high-speed ^ which requires a high level and a low-speed processing which requires a process, and a high-speed timer counter for generating the high-level reference clock, and a clock for: Timer counter Control device for gas lasers, where each processing timing is determined in advance.

(12) The control items in the high-speed processing are at least output of a discharge start signal, detection of a laser output and output of a stabilization control signal thereof, detection of a laser wavelength and output of a stabilization control signal thereof, and The control item in & ¾Process¾ ^ is at least the output of the gas valve opening / closing control signal in the gas, and is set to 16:

11. The control device for a gas laser according to 1.